Fire barriers for gas-cylinder storage in vehicles

March 4, 2004

Mr. John D. Evans

Vice President Engineering

The Knapheide Manufacturing Company

[Recipient address omitted]

Dear Mr. Evans:

This is in response to your letter dated August 7, 2003, to the Occupational Safety and Health Administration (OSHA) concerning §1926.350(a)(10). You indicate that you propose to design a container with a fire-resistant barrier that will comply with the above standard.

We have paraphrased your questions as follows:

Question 1: Is ASTM E119 the correct testing standard to be used for determining if a 6 ft2 fire-resistance barrier in a vehicle's gas cylinder storage compartment [that] meets the half-hour fire rating required in §1926.350(a)(10)? If not, what testing standard would apply?

Answer

Section 1926.350(a)(10) states:

Oxygen cylinders in storage shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet (6.1m) or by a noncombustible barrier at least 5 feet (1.5m) high having a fire-resistance rating of at least one half hour.

The term "fire-resistance rating" has traditionally been used in the industry to refer to a time period of fire-resistance determined in accordance with a viable testing protocol. Although the ASTM E119 standard is recognized by the industry as a viable testing protocol for evaluating fire-resistance of buildings, it is not designed to evaluate the fire-resistance of equipment. The standard's test methods:

prescribe a standard fire exposure for comparing the test results of building construction assemblies.1

The ASTM standard requires a testing sample not less than 100 ft2 for bearing walls, nonbearing walls, and partitions and at least 180 ft2 for floors and roofs. The standard's tests and conditions of acceptance (the length of time material will be deemed fire-resistant) are based on this minimum sample size. Since the barrier you need to test is only 6ft2, you would not be able to meet the E119 testing protocol. E119 would therefore be inappropriate for evaluating the fire-resistance of the vehicle gas cylinder storage compartment you have designed.

The OSHA standard does not specify a particular testing protocol that must be used to determine whether the half-hour fire rating has been met. We are not aware of any industry consensus standards designed to assess fire-resistance of barriers in vehicles. A fire-resistance testing protocol for a barrier in a vehicle designed by a registered professional engineer familiar with fire-resistance testing would be acceptable. Similarly, a testing protocol developed by a Nationally Recognized Testing Laboratory2 would also be acceptable.

Question 2: Is there a minimum width for fire barriers required under §1926.350?

Answer

No, there is no specification requirement in §1926.350 for fire barrier width.

Question 3: Is there an OSHA construction standard that specifies a minimum size for gas cylinder compartment vent openings?

Answer

There is no OSHA construction standard that sets a minimum-size requirement for such vents. However, you may want to contact the Department of Transportation to find out if it has such requirements.3

Question 4: Section 1926.350(a)(10) states that the fire barrier must be at least "5 feet (1.5m) high." 1.5 meters is 59.06 inches. Does a fire wall that is 59.06 inches or greater meet this requirement?

Answer

Yes. By its terms, a barrier that is 1.5 meters high meets the height requirement in §1926.350(a)(10), since that provision specifically states that 1.5 meters is acceptable. If a proposed fire wall exceeds either 5 feet (60 inches) or 1.5 meters (the equivalent of 59.06 inches), the height requirement is met.

Question 5: Does OSHA have any requirements for labeling the fire wall with a certification of fire-resistance?

Answer

No.

If you need additional information, please contact us by fax (202-693-1689) at: U.S. Department of Labor, OSHA, Office of Construction Standards and Guidance. You can also contact us by mail at U.S. Department of Labor, OSHA, Office of Construction Standards and Guidance, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.

Sincerely,

Russell B. Swanson, Director

Directorate of Construction

1ASTM E119 1.4. [ back to text ]

2The term "nationally recognized testing laboratory" (NRTL) means an organization that is recognized by OSHA in accordance with Appendix A of 29 CFR 1910.7 and which tests for safety, and lists or labels or accepts, equipment or materials and which meets all of the criteria listed in §1910.7(b). [ back to text ]

3You may contact DOT's Assistant General Counsel for Regulation and Enforcement at: (202) 366-4723. [ back to text ]